Fin and Heat Sink

ABSTRACT

A fin is penetrated through by a heat pipe. The fin includes a fin body and a plurality of positioning protrusions. The fin body has an accommodating hole penetrated by the heat pipe. The positioning protrusions are formed at the circumference of the accommodating hole for holding against the heat pipe, so that a gap is provided between the heat pipe and the circumference of the accommodating hole.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No(s). 096147970 filed in Taiwan, Republic ofChina on Dec. 14, 2007, the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a thermal conducting element and, inparticular, to a fins assembly and a heat sink.

2. Related Art

According to the progress of technology, the integration of electronicdevices has been continuously increased. Thus, the electronic apparatusgenerate more heat when it is working. Therefore, it is an importantsubject to increase the heat dissipating efficiency so as to maintainthe operation stability of the electronic apparatus. In general, a heatsink, which includes a fins assembly and a heat pipe, is applied tosolve this problem.

As shown in FIG. 1A, a conventional heat sink 1 includes a fins assembly11 and a heat pipe 12. The fins assembly 11 is composed of a pluralityof fins 111, which are connected with each other. The fins 111 form anaccommodating hole 112 for accommodating the heat pipe 12. Afterdisposing the solder paste between the fins assembly 11 and the heatpipe 12 and heating the solder paste, the fins assembly 11 and the heatpipe 12 can be relatively fixed by the solder paste. In general, thereare two methods for disposing the solder paste between the fins assembly11 and the heat pipe 12, which will be described hereinbelow.

The first method for disposing the solder paste between the finsassembly 11 and the heat pipe 12 is to inject the solder paste throughan injection portion 112 a (such as a hole) formed on the accommodatinghole 112 after the heat pipe 12 is inserted into the accommodating hole112. In detailed, an injection needle N is inserted into the injectionportion 112 a, and then the solder paste is injected and filled betweenthe fins assembly 11 and the heat pipe 12. After that, the solder pasteis heated so as to fix the fins assembly 11 and the heat pipe 12.However, due to the error caused by the manual operation or machines,the amount of the injected solder paste can not be precisely controlledand the thickness of the solder paste may be non-uniform. This willdecrease the combination strength between the fins assembly 11 and theheat pipe 12, thereby affecting the heat dissipating efficiency. Inaddition, the configuration of the injection portion 112 a decreases thetotal heat dissipating area of the fins assembly 11, and the process ofinjecting the solder paste may take a long time so as to increase themanufacturing cost.

As shown in FIG. 1B, the second method for disposing the solder paste,which does not need the injection portion 112 a, is to dispose thesolder paste 121 on the outer surface of the heat pipe 12 and theninsert the heat pipe 12 into the accommodating hole 112 of the finsassembly 11. However, since no fixing mechanism is provided, a part ofthe solder paste 121 disposed on the heat pipe 12 may be scraped off bythe accommodating hole 112 when inserting the heat pipe 12 into theaccommodating hole 112. Moreover, the solder paste 121 may be pushed andoverflow through the other end of the accommodating hole 112, so that itis necessary to remove the overflowed solder paste by manual. This alsocauses the non-uniformity of the solder paste and thus decreases thecombination strength between the fins assembly 11 and the heat pipe 12.

Therefore, it is an important subject to provide a fin and a heat sinkthat can increase the reliability and throughput.

SUMMARY OF THE INVENTION

In view of the foregoing subject, an object of the invention is toprovide a fin and a heat sink that can increase the reliability anddecrease the manufacturing cost.

To achieve the above object, the invention discloses a fin, which ispenetrated by a heat pipe. The fin includes a fin body and a pluralityof positioning protrusions. The fin body has an accommodating hole, andthe heat pipe penetrates through the accommodating hole. The positioningprotrusions are formed at the circumference of the accommodating holefor holding against the heat pipe, so that a gap is provided between theheat pipe and the circumference of the accommodating hole.

In addition, the invention also discloses a heat sink including a finsassembly and a heat pipe. The fins assembly includes a plurality of finsconnected with each other. Each fin includes a fin body and a pluralityof positioning protrusions. The fin has an accommodating hole, and thepositioning protrusions are formed at the circumference of theaccommodating hole. The accommodating holes of the fin bodies arealigned with each other. The heat pipe penetrates through theaccommodating holes and is held by the positioning protrusions, so thata gap is provided between the heat pipe and the circumferences of theaccommodating holes.

As mentioned above, the fin and heat sink of the invention have thepositioning protrusions disposed on the circumference of theaccommodating hole for holding against the heat pipe. Thus, a gap can beprovided between the heat pipe and the circumferences of theaccommodating holes, thereby preventing the thermo-conductive mediumdisposed on the outer surface of the heat pipe from being scraped off orpushed out. Accordingly, the combination strength of the heat pipe andthe fins can be controlled, so that the reliability of the product canbe increased. In addition, since the thermo-conductive medium is notpushed out or scraped off, the action of removing the overflowedthermo-conductive medium is unnecessary, so that the manufacturing costcan be reduced. Moreover, the thermo-conductive medium is disposed onthe outer surface of the heat pipe, so the process for disposing thesolder paste can be speeded up, thereby increasing the throughput. Inaddition, the thermo-conductive medium disposed on the outer surface ofthe heat pipe can be more uniform so as to increase the combinationstrength of the heat pipe and the fins. Furthermore, since the injectionhole of the fins assembly is unnecessary in this invention, the heatdissipating area of the fins can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription and accompanying drawings, which are given for illustrationonly, and thus are not limitative of the present invention, and wherein:

FIGS. 1A and 1B are schematic diagrams of disposing the solder paste onthe conventional heat sink;

FIG. 2 is a schematic diagram showing a heat sink according to apreferred embodiment of the invention; and

FIG. 3 is a sectional diagram of the heat sink according to thepreferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings,wherein the same references relate to the same elements.

FIG. 2 is a schematic diagram showing a heat sink 2 according to apreferred embodiment of the invention. The heat sink 2 includes a finsassembly 21 and a heat pipe 22. FIG. 3 is a sectional diagram of theheat sink 2, wherein the heat pipe 22 has penetrated through theaccommodating holes 212 of the fins 211. The heat sink 2 will bedescribed hereinbelow with reference to FIGS. 2 and 3.

The fins assembly 21 includes a plurality of fins 211 connected witheach other. Each fin 211 includes a fin body F and a plurality ofpositioning protrusions 213. The fin body F has an accommodating hole212, and the accommodating holes 212 of the fin bodies F are alignedwith each other. The heat pipe 22 can penetrate through theaccommodating holes 212. The positioning protrusions 213 are formed atthe circumference of at least one of the accommodating holes 212. In theembodiment, the positioning protrusions 213 of the fins 211 are alsoaligned and disposed on a straight line. Alternatively, the positioningprotrusions 213 can be randomly arranged.

In the embodiment, the accommodating hole 212 can be, for example butnot limited to, circular, elliptical, flat or polygonal. Preferably, theshape of the heat pipe 22 must match the accommodating hole 212. Inaddition, the shape or aspect of the positioning protrusions 213 can be,for example but not limited to, a protruding point or a rib. Thepositioning protrusions 213 and the fin body F can be integrally formedby punching. Alternatively, the positioning protrusions 213 can beadditional added elements. For example, the positioning protrusion 213can be a protruding point or a rib, which is formed on the circumferenceof the accommodating hole 212 by wedging or adhering.

The heat pipe 22 penetrates through the accommodating holes 212 and isheld by the positioning protrusions 213, so that a gap G can be providedbetween the heat pipe 22 and the circumferences of the accommodatingholes 212. In the embodiment, a thermo-conductive medium 221 is disposedon at least one portion of an outer surface 222 of the heat pipe 22. Thethermo-conductive medium 221 includes a solder paste, a thermal adhesiveor other thermo-conductive material. In the embodiment, thethermo-conductive medium 221 can be formed on the outer surface 222 ofthe heat pipe 22 by screen printing, coating or adhering. The area ofthe thermo-conductive medium 221 can be determined according to theactual need. For example, the thermo-conductive medium 221 can be formedon the whole outer surface 222 or another surface opposite to the outersurface 222. In the embodiment, the thermo-conductive medium 221 isformed on the top and bottom surfaces of the heat pipe 22.

Since the positioning protrusions 213 are disposed on the circumferenceof the accommodating hole 212, the positioning protrusions 213 canthrust against the heat pipe 22, so that a gap G can be provided betweenthe heat pipe 22 and the circumference of the accommodating hole 212.Due to the gap G, the thermo-conductive medium 221 will not be pushedout or scraped by the circumference of the accommodating hole 212 wheninserting the heat pipe 22 into the accommodating hole 212. The gap G ispreferably equal to or slightly larger than the thickness of thethermo-conductive medium 221. In the embodiment, the number ofpositioning protrusions 213 is not limited and must be two or more. Thepositioning protrusions 213 are disposed corresponding to thethermo-conductive medium 221. For example, the positioning protrusions213 can be disposed on one side of the accommodating hole 212, which isadjacent to the thermo-conductive medium 221. In addition, thepositioning protrusions 213 can be located on opposite sides of theaccommodating hole 212 or symmetrically disposed on the circumference ofthe accommodating hole 212.

In addition, each fin body F may include at least one hollow portion214, which is disposed adjacent to one of the positioning protrusions213. In the embodiment, two hollow portions 214 are disposed adjacent totwo sides of the positioning protrusions 213. The hollow portions 214can make the punching process of forming the positioning protrusions 213much easier. In addition, the hollow portions 214 can provide thestructural flexibility for facilitating the positioning protrusions 213to guide the heat pipe 22 into the accommodating hole 212.

In the embodiment, the heat pipe 22 has an enclosed chamber and acapillary structure disposed on the inner wall thereof. In addition, theheat pipe 22 contains a work fluid therein. One end of the heat pipe 22is an evaporation end A, and the other end thereof is a condensation endB. The evaporation end A is in contact with a heat source (not shown).The work fluid located around the evaporation end A can absorb the heatand then be evaporated into the gas state. The gas-state work fluidflows toward the condensation end B due to the pressure difference.Then, the gas-state work fluid can release the latent heat around thecondensation end B and be condensed into the liquid state. The condensedwork fluid can flow back to the evaporation end A according to thecapillarity of the capillary structure. This loop of the work fluid canachieve the heat dissipating effect. The fins assembly 21 can bedisposed around the condensation end B for helping to dissipate the heatgenerated by the heat source. In the embodiment, the heat sink 2 can beapplied to various kinds of electronic device, which can generate heat,such as the CPU chip, display chip or graphic chip of the notebookcomputer.

With reference to FIGS. 2 and 3 again, the invention also discloses afin 211, which is cooperated with a heat pipe 22. The fin 211 includes afin body F and a plurality of positioning protrusions 213. The fin bodyF has an accommodating hole 212, and the heat pipe 22 can penetratethrough the accommodating hole 212. The positioning protrusions 213 areformed at the circumference of the accommodating hole 212 and holdagainst the heat pipe 22, so that a gap G can be provided between theheat pipe 22 and the circumference of the accommodating hole 212. Thefunctions and features of the fin 211 are the same as those describedabove, so the detailed descriptions will be omitted.

To sum up, the fin and heat sink of the invention have the positioningprotrusions disposed on the circumference of the accommodating hole forholding against the heat pipe. Thus, a gap can be provided between theheat pipe and the circumferences of the accommodating holes, therebypreventing the thermo-conductive medium disposed on the outer surface ofthe heat pipe from being scraped off or pushed out. Accordingly, thecombination strength of the heat pipe and the fins can be controlled, sothat the reliability of the product can be increased. In addition, sincethe thermo-conductive medium is not pushed out or scraped off, theaction of removing the overflowed thermo-conductive medium isunnecessary, so that the manufacturing cost can be reduced. Moreover,the thermo-conductive medium is disposed on the outer surface of theheat pipe, so the process for disposing the solder paste can be speededup, thereby increasing the throughput. In addition, thethermo-conductive medium disposed on the outer surface of the heat pipecan be more uniform so as to increase the combination strength of theheat pipe and the fins. Furthermore, since the injection hole of thefins assembly is unnecessary in this invention, the heat dissipatingarea of the fins can be increased.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiments, as well asalternative embodiments, will be apparent to persons skilled in the art.It is, therefore, contemplated that the appended claims will cover allmodifications that fall within the true scope of the invention.

1. A fin, which is cooperated with a heat pipe, comprising: a fin bodyhaving an accommodating hole, wherein the heat pipe penetrates throughthe accommodating hole; and a plurality of positioning protrusionsformed at the circumference of the accommodating hole and holdingagainst the heat pipe, so that a gap is provided between the heat pipeand the circumference of the accommodating hole.
 2. The fin according toclaim 1, wherein the accommodating hole is circular, elliptical, flat orpolygonal.
 3. The fin according to claim 1, wherein a thermo-conductivemedium is disposed on at least a portion of an outer surface of the heatpipe.
 4. The fin according to claim 3, wherein the thermo-conductivemedium comprises a solder paste or a thermal adhesive.
 5. The finaccording to claim 3, wherein the positioning protrusions are located onone side of the accommodating hole adjacent to the thermo-conductivemedium.
 6. The fin according to claim 1, wherein the positioningprotrusions are located on opposite sides of the accommodating hole. 7.The fin according to claim 1, wherein the positioning protrusions aresymmetrically disposed on the circumference of the accommodating hole.8. The fin according to claim 1, wherein each of the positioningprotrusions comprises a protruding point or a rib.
 9. The fin accordingto claim 1, wherein the fin body comprises at least one hollow portiondisposed adjacent to one of the positioning protrusions.
 10. A heatsink, comprising: a fins assembly comprising a plurality of finsconnected with each other, wherein each of the fins comprises a fin bodyhaving an accommodating hole and a plurality of positioning protrusionsformed at the circumference of the accommodating hole, and theaccommodating holes of the fin bodies are aligned with each other; and aheat pipe penetrating through the accommodating holes and held by thepositioning protrusions, so that a gap is provided between the heat pipeand the circumferences of the accommodating holes.
 11. The heat sinkaccording to claim 10, wherein the accommodating hole is circular,elliptical, flat or polygonal.
 12. The heat sink according to claim 10,wherein a thermo-conductive medium is disposed on at least a portion ofan outer surface of the heat pipe.
 13. The heat sink according to claim12, wherein the thermo-conductive medium comprises a solder paste or athermal adhesive.
 14. The heat sink according to claim 12, wherein thepositioning protrusions are located on one side of the accommodatinghole adjacent to the thermo-conductive medium.
 15. The heat sinkaccording to claim 10, wherein the positioning protrusions are locatedon opposite sides of the accommodating hole.
 16. The heat sink accordingto claim 10, wherein the positioning protrusions are symmetricallydisposed on the circumference of the accommodating hole.
 17. The heatsink according to claim 10, wherein the positioning protrusions and theaccommodating hole are integrally formed by punching.
 18. The heat sinkaccording to claim 10, wherein each of the positioning protrusionscomprises a protruding point or a rib.
 19. The heat sink according toclaim 10, wherein the fin body comprises at least one hollow portiondisposed adjacent to one of the positioning protrusions.